Recently, with the widespread use of the Internet as a background, browsing contents described by a markup language such as an HTML (hypertext markup language) is performed on various types of terminal devices, such as a mobile phone, a PDA (personal digital assistant), a household electric appliance and a car navigation system, as well as a personal computer. In general, a software called a browser is used to execute the browsing of contents.
FIG. 4 is a flowchart illustrating a rendering process of a conventional browser running on a personal computer. As shown in FIG. 4, the browser starts obtaining a web page designated by a user through a network (step S11). In subsequent steps S12 through S15, it is judged whether external cascading style sheets (external CSS) and an external script are included in the obtained web page (i.e., the obtained HTML document), and thereafter the external CSS and the external script are obtained if they are included in the obtained web page.
The “external CSS” means a CSS to be obtained through a network. The “external script” means a script to be obtained through a network.
When the external CSS is included in the obtained web page (S12:YES), the external CSS is obtained through the network (S13). Then, control proceeds to step S14. When the external CSS is not included in the obtained web page (S12:NO), control proceeds to step S14.
In step S14, it is judged whether the external script is included in the obtained web page. When the external script is included in the obtained web page (S14:YES), the external script is obtained through the network (S15). Then, control proceeds to step S16. When the external script is not included in the obtained web page (S14:NO), control proceeds to step S16. In step S16, rendering of the obtained web page (i.e., displaying operation of the obtained web page) is executed.
As can be seen from the flowchart shown in FIG. 4, the conventional browser does not perform displaying operation of a web page until acquisition of external data (i.e., an external CSS and an external script) is completed. That is, a screen image of a web page designated by a user is not displayed on a screen until a time period from step S11 to step S15 has elapsed. The reason is that the style sheet and the script are data to be applied to the entire web page to be processed, and therefore the obtained web page can not be displayed as intended by a designer of the web page until the external data is completely obtained.
Accordingly, the user is required to wait until the displaying of a web page is started at step S16 after the designation of the web page.
In a publication, “Web technology with illustrations by diagrams”, Osamu Koizumi, Nihon Jitsugyo Publishing CO., LTD, Nov. 10, 2001, pages 131-136 and pages 140-142, a property of a script is described. That is, it is disclosed in the publication that the style sheet is information to be applied to the entire web page.
W3C Recommendation concerning the style sheet is also explained in detail in a publication, “W3C Recommendation Cascading Style Sheet Level 1”, which can be obtained from a URL: http://www.w3.org/TR/CSS1.
It should be note that although in the flowchart in FIG. 4 the presence or absence of the external CSS and the external script is judged in this order in accordance with a typical structure of a web page. However, the order of designation of the external CSS and the external script varies among web pages because the order is decided by a designer's intention. Therefore, modifications of the flowchart of FIG. 4 (e.g., a modification in which the order of step S12 and step S14 is reversed) can be made depending on the type of a targeted web page.